Apparatus for recording information upon a record medium



APPARATUS FOR RECORDING INFORMATION UPON A RECORD MEDIUM Filed Dec. 7, 1959 Feb. 18, 1964 J. T. MGNANEY 2 Sheets-Sheet 1 INVENTOR. JOSEPH T. MCNANEY Feb. 18, 1964 J. T. MONANEY 3,121,873

APPARATUS FOR RECORDING INFORMATION upon A RECORD MEDIUM Filed Dec'. 7, 1959 2 Sheets-Sheet 2 Flg 3 INVENTOR.

JOSEPH T. MCNANEY.

United States Patent 3,121,873 APPARATUS FQR RECQRDING INFQRMATION UPON A RECGRD MEDIUM Joseph T. McNaney, La Mesa, Calif., assignor to General Dynamics Corporation, Rochester, N.Y., a corporation of Delaware Filed Dec. 7, 1959, Ser. No. 857,958 7 Claims. (Cl. 346-74) The invention relates generally to recordation of information utilizing electrical charge patterns. A development in this field closely allied to the instant invention has been designated as electrophotography or xerography.

In the normal practice of xerography, an electrostatic charge is applied to a free surface of a photoconductive insulating layer. The photoconductive insulating layer has its other surface backed by a transparent conductor layer. Illumination of select portions of the photoconductive insulating layer will cause the illuminated portions to become conductive, thereby causing the charge disposed upon the free surface of the photoconductive layer to be conducted therefrom to the conductor layer. In this manner, a pattern of light and shadow may be recorded on the free surface of the photoconductive layer as areas of differing electric charge conditions. In the usual practice of xerography, electrostatically attractable material is then disposed upon or against the free surface of the photoconductive layer, so that the electrostatically attractable material, depending upon its charge, will adhere only to one of the two charged conditions upon the free surface of the photoconductive layer. The electrostatically attractable material then presents a visible image of the light and shadow charge pattern presented on the free surface of that photoconductive layer. The electrostatically attractable material may then be transferred to an insulating layer for transfer to a final record medium, or directly transferred from the surface of the photoconductive layer of the final record medium. The material thereafter may be fused into the record medium by application of heat thereto, and glazed if preferred, in order to insure the permanency of the recordation.

One of the requirements in utilizing xerography, as presently understood, is the establishment of potential fields giving rise 'to appropriate current paths throughout the entire xerographic operation. That is, the sources of potential must be applied across predetermined air gaps, slightly conductive insulators, and the like, all to aid in transferring charges, by conduction, between the record medium, the photoconductive layer, or the insulating layer. All are under the influence of the source of potential and minute currents therefrom flow across the air gap in be: tween the two adjacent members. The establishment of such fields, the use of currents, all tend to limit the life of the various components in the practice of xerography. Further, in such practice, rather high voltages utilizing small currents require expensive, well-regulated power supplies. In order to minimize some of the aforestated difliculties, and to simplify materially the recordation of information upon the record medium, the instant invention is directed.

The present invention, which is an improvement upon my cope-nding application Serial No. 739,034, filed June 2, 1958, now Patent No. 3,066,298 and assigned to the same assignee, utilizes a record medium capable of holding for a short duration of time, at least, an electrostatic charge pattern. The record medium may be charged in various I known ways, for example, by the application of corona charge applied to the surface of the record medium. Such charge application is usually effected by very minute' currents, under the influence of rather high potential sources. The charge, in effect, migrates from the elements on which it is created, to an area adjacent the record medium, mi-

3,121,873 Patented Feb. 18, 1964 'ice grating thereto as a corona discharge. The record medium, charged in this manner, is then placed in a spacedapart relation, but in close proximity to a conversion unit or converter means, capable of transforming light images into electric potential charge patterns. The electric potential charge pattern or the charge disposition so established thereon, should be such that it is capable of altering the charge upon the record medium. The electric potential charge disposition is exemplified as being in a polarity opposed to the polarity of the change carried on the record medium, in order to adequately explain the operation as I understand it.

The converter means may be exemplified as a unit including a photoconductor whose free surface is positioned adjacent but spaced apart from the record medium. The other surface of the photoconductor is disposed adjacent an elongated light pipe or guide, and photoconductor construction at Whose terminus is disposed an optically transparent conductive layer. The source of potential, variable if desired, is then applied to the conductive layer and across the light pipe and photoconductor construction for selective application onto the photoconductor surface, whereby the source is selectively presented to the record medium. The source may have voltages which provide a polarity opposed to, or capable of neutnallizin reonienting or attracting the charge existing upon the record medium. It is an essential element of the present invention that the charge pattern upon the record medium be changed or altered by electrical potential influence or direct charge transfer, for thus recording the desired information thereupon.

Subsequent light irradiation of the converter means, including its photoconductor layer, the light pipes and photoconductor construction and the conductor layer, will cause the irradiated portions of the converter means to create conductivity upon the photoconductor, thereby, presenting the voltage impressed thereupon adjacent the record medium, to alter the electrical conditions thereon, in conformity with the irradiated pattern presented to the photoconductor. A more exacting description of the electrical adteration of the charge on the record medium is not presently perfectly understood, but it is known that the voltage may be directly applied, thereby transferring the charge by conduction from the record medium in the irradiated area, or indirectly by its influence in spaced apart relation, altering the charge pattern upon the medium. The unirradiated areas of the photoconductor will appear on the record medium as still charged with the original charge disposed thereupon by the corona charging. T .e record medium therefore presents the electric charge pattern record of the light information.

If desired, through the practice, then, of well known techniques of xerography, electrostatically attractable materials of opposite polarity to that of the change pattern, may then be utilized to effect a positive Visual indication of the electrostatic record upon the record medium.

As the present invention alters, neutralizes or dissipates the charge upon the record medium, in correspondence with the light information to be recorded thereupon, and the ,photoconductor does not have any electrostatically attractable material upon its surface, it can be readily seen that the life span of the photoconductor 'hasfbeen immeasurably increased over the prior-art constructions. Further, the normal problems of charge migration are mitigated over those normally present in the photoconductors physical transfer arrangements in which the visual pattern is formed on the photoconductor and transferred by direct contact with and against the record medium. As the instant invention merely alters, neutralizes, or dissipates the charge electrostatically, it can further beseen that the source of potential utilized With the photoconductor need not be an exacting or highly a conductive backing 18 to ground.

regulated source, nor need it have any considerably current delivering ability; it being merely desired to present voltage sufficient to alter, attract, or neutralize the charge appearing on the record medium, or the direct neutralizing of the charge, no substantial current transfer being effected with respect to the record medium. The instant invention therefore creates latent images, not by embodying latent charge images upon the record medium, but

rather by changing or discharging discrete areas of latent charges of a normally charged record medium, for subsequent development of the remaining charged area.

In addition to objects and advantages as aforestated, it is an object of the present invention to provide a simple and inexpensive apparatus for recording light information upon a relatively inexpensive record medium.

It is another object of the present invention to provide an apparatus for recording information as selective charge patterns upon a record medium which is capable of sim ple operation and trouble-free constructional design.

Objects and advantages other than those set forth above will become apparent when read in connection with the accompanying specification and drawings in which:

FIGURE 1 is a schematic perspective representation embodying the present invention;

FIGURE 2 is a schematic representation of the invention of FIGURE 1 demonstrating its operation; and

FIGURE 3 is a fragmentary enlarged cross section showing the converter means construction in greater detail.

The invention as shown in FIGURE 1 basically includes recordation in electric charge pattern form, of light information upon a record medium 10. The charge pattern may be subsequently developed into visual images. The record medium should be capable of accepting and holding, for a short duration of time, an electrostatic charge. The charge may be applied by a corona charging unit 11, including a high voltage source, and several wires from which the corona may be generated. The record medium is preferably uniformly charged upon its surface, and so is presented to an assembly 12, under the influence of a source of potential 13, and light irradiation 14. The total assembly 12 may be designated as a converter means capable of converting the light ray information into electrical poten tial charge patterns, to effect electrical influencing of the charges carried by the record medium. The electric potential charge arranged in patterns determined by the light irradiation will, when placed into electrical contact with the charge on the surface of the record medium, or in close spaced-apart physical proximity thereto, alter, dissipate, or neutralize the charge on the record medium, in accordance with the areas of irradiation of the assembly 12. The charges, as changed on the record medium 10, may thereafter be transferred from the record medium onto another record medium, or, as herein exemplified, may then be developed directly onto the record medium, through the use of electrostatically attractable materials 15, such as practiced in the prior Xerographic .art. Subsequently, heat may be used to fuse the material 15 into the record medium to provide a permanent record.

In greater detail, and to further explain the invention, FIGURE 1 shows the record medium 10 travelling between several pairs of rollers and first presenting an area on the medium to the conductors 16 of the corona charging unit 11. The conductors or wires 16 may be energized by high voltage source 17 to a point at which charges are emitted in the form of corona, from the wires, some of which are deposited upon the record medium, thus completing the low'current path through It must be understood that the present corona schematics as exemplified in FIGURES 1 and 2 are not intended to so limit the invention. There are other known ways of effecting electrostatic charge disposition upon a material capable of holding charges, such as spraying the surface with positive and negative ions or the like. It is merely desired herein to exemplify one way of charging the record medium.

The record medium 19 may utilize any well known paper, and such paper may not necessarily be a special paper. Ordinarily utilized papers, glazed or unglazed, will accept charges and retain them for a short duration of time. The short period of time may be measured in seconds. Usually, the time depends upon the transport of the record medium from charging to charge alteration, or from recording the information to development. Of course, longer duration of storage of information as charges is also contemplated. Transport mechanisms exist which are capable of transporting a medium from one station to another and completing the entire cycle from initial charging through recordation and develop ment, in about 2 to 8 seconds. Of course, if longer time duration is desired between various transport stages, the record medium must be capable of holding its charge pattern for such a desired longer period.

After a charge has been disposed upon the record medium under the influence of conductors 16, the record medium 10 may be transported to a station opposing the light to electrons converter or converter means 12. The converter means 12 may effect conversion of light to electric charge potential and by its placement present such charge to influence the charge on the record medium. Assembly 12 may include a conductive layer 20, and a photoconductive layer 22. The conductive layer 29 is light transparent as well as of low electrical resistance, and may utilize conductive type glass known by the trademark NESA made by the Pittsburgh Plate Glass Company of Pittsburgh, Pennsylvania. Intermediate the conductive layer 20 and the photoconductive layer 22, is disposed a plurality of light pipes or light guides spaced from each other by predetermined layers of photoconductor as an assembly 19. In detail, assembly 19 includes light pipes 40. Light pipes or guides 40 utilized herein may be of the type made by the American Optical Company of Boston, Massachusetts. These light pipes are electrical insulators, and are generally made in an elongated construction to transmit light from one end of the elongation to the other end, with a minimum amount of light lost therebetween. The light is primarily transmitted from the one end to the other end of the elongation and as it does so, it generally illuminates its sides along the elongation. Light pipes 40 are spaced from each other by a predetermined spacing. Disposed intermediate each of the light pipes 40 within the predetermined spacing is an elongated photoconductor 42 or a layer thereof. The photoconductor 42 is an electrical connection with the conductive layer 20 and the photoconductor layer 22. In many applications, relatively high potentials may be desirably utilized to eifect the change, altering or neutralizing the latent charges upon the record medium. To do so, the present improvement is directed. In order to achieve maximum efficiency of the photoconductor and its change of resistance characteristics in the presence of light, relatively thin layers thereof should preferably be used. The thin layers thereof will assure the light passage through the photoconductor, rendering it conductive throughout its structure. Therefore, in my preferred embodiment, the light guides or pipes 40 with the thin layers 42 of photoconductor separating the pipes 40, provide the length of layers 42 as the separating resistances between layers 20 and 22. As light is presented from source 24 to unit or assembly 12, selected light guides 40 transmit the light to. layer 22, as well as provide light to the adjacent layers 42. The adjacent layers 42 therefore will become conductive in the light excited areas and present the impressed voltage or potential to photoconductorlayer 22.

In operation, therefore, the converter means 12 will transmit light from source 24 onto and through the conductive layer 20 to illuminate selected light pipes 40. Light pipes 40 will transmit the light to in turn cause the photoconductive material or layer adjacent the elongated surfaces of light pipes 40 to become conductive, thereby transmitting from the conductive layer 20 to the photoconductive layer 22 the potential impressed to the photoconductive layer 22. The light transmitted by the light pipe 40 also causes the layer 22 adjacent the extremity or end of the light pipe 40 to become conductive. Therefore, the potential impressed upon assembly 12 is presented adjacent the record medium, in the selected area of irradiation.

The free surface 23 of the photoconductive layer 22 is of course positioned adjacent and may be in actual contact with or may be in spaced-apart relation from the record medium It The spacing intermediate surface 23 and medium 19 is such that the potential charge on the surface 23 will permit reorientation of the charge on the record medium it), either to alter, neutralize, or dissipate such last-stated charges. Connected with the conductive layer 20 is, of course, the source of potential 13. Source 13 is capable of presenting the predetermined voltage across the converter means 19, and at and adjacent the record medium 16 at the surface 23. The predetermined voltage is exemplified as establishing upon the conductive layer 20 an electric potential charge disposition of polarity opposed to predetermined polarity of the charge substantially uniformly disposed upon the record medium 10. Information presented from a source 24 in the form of light rays 14 and light and shadow causes irradiation of corresponding patterns through the converter means 19' upon the photoconductive layer 22. The resulting illumination will be transmitted through the conductive layer 20 and by the light pipes 40 to the selected irradiated areas of the photoconductive layer 22, which becomes conductive in those irradiated areas, thereby presenting at the outer surface 23 the electric potential charges established by the source of potential 13, as shown and exemplified in FIGURE 2 as negative. The charges on the record medium are exemplified as positive.

Presentation of the information of negative charges in close proximity to the positive charges on the record medium is believed to cause an electrical influence or re-orientation of the charges on the record medium. If the invention is practiced by using actual contact, posi 'tive charges may be conducted away from the record medium, or dissipated to ground. When the invention utilizes spacing of positive surface 23 from the record medium 19, it is believed that the electrostatic or electrical influence existing between the charges of different signs (basically different degrees of potential) causes imposed upon conductor 20, may have neutralized, at-

tracted, altered or dissipated the opposite polarity charge on the record medium. It is believed that the electrical influence may be stated to be electrostatic charge influence. Therefore, the pattern of light and shadow as presented by light rays'14 appears on the record medium 10, 'exemplarily shown as area 25, devoid of charges, alternate areas 26 retaining the original charges upon "he record medium, thus presenting the light and shadow pattern recorded.

Subsequent transport of the record medium It) from the position adjacent the converter means 19 from which development of the charged and uncharged area 25, 26, utilizing electrostatically attractable material 15, and converting such areas into visual patterns of light and shadow. Such development may, of course, be accomplished in any of the well known prior-artteachings, as shown,

for example, in US. Patent 2,659,670, 2,701,765, or

may also after such fusing be overcoated with glazes of various types, used in the printing business, to further aid in preserving the permanent record on the record medium of the information originally presented thereto, in the form of light and shadow.

The particular embodiments of the invention illustrated and described herein are illustrative only, and the invention includes such other modifications and equivalents as may readily appear to those skilled in the arts, and within the scope of the appended claims.

I claim:

1. Means for recording light information electrostatically upon a record medium comprising said record medium having electric charges disposed upon one of its surfaces, said charges being of a predetermined polarity and magnitude with respect to a fixed reference potential, a photoconductive layer disposed adjacent but spaced apart from said record medium, a conductive transparent layer, a plurality of elongated light guides bundled together in spaced apart relation one to the other defining therebetween along the elongation of said guides a predetermined spacing, photoconductive material disposed within said spacing along said elongated light guide for responding to light from the adjacent guide to render the adjacent photoconductive material conductive, said light guide and said photoconductive material assembly being interposed between and contiguous with said conductive layer and said photoconductive layer, a source of potential presenting at least a predetermined voltage opposite in polarity to said predetermined polarity, said predetermined voltage being connected with that conductive layer and establishing thereon an electric potential charge disposition of a polarity opposing said predetermined polarity, and means for selectively irradiating said light guides and said photoconductive material to activate said photocon-ductive layer so as to present that polarity in electric charge infiuencing'relation to the charge disposition of said predetermined polarity, said predetermined magnitude of the charge on said record medium and the magnitude of said charge patterns being sufficient to create a change in the charge disposition of said predetermined polarity solely in response thereto to thereby create a charge pattern upon said record medium in conformity with the said charge pattern on said photoconductive layer.

2. Means for electrostatically recording light information upon a record medium having an electric charge of a given polarity with respect to a fixed reference potential disposed upon one of its surfaces, a source of potential presenting a voltage of predetermined magnitude with respect to said fixed reference potential, said voltage being opposite in polarity to said predetermined polarity, converter means for changing the light information into correspondingly shaped electrical charge patterns on a given surface of said converter, said converter means comprising a plurality of elongated light guides spaced apart one from another defining the-reb-etween a predetermined spacing, photoconductive material disposed within said spacing along said elongated light guides, a photoconductive layer across one of the ends of each of said light guides, said layer being in contact vith said photoconductive -ma terial, said photoconductive layer forming at least a portion of said given surface, means for connecting said source of potential to said photoeonductive material at a point remote from its juncture with said photoconductive layer, and means for selectively irradiating the other ends of said light guides in accordance with the light information to be recorded to selectively apply said opposite polarity to said given surface to provide charge patterns shaped in accordance With said light information, said 'given surface of said converter being supported in electrostatic charge influencing position with respect to said one "surface of said record medium, said predetermined magnitude of the charge on said record medium and the magnitude of said charge patterns being sufiicient to create a change in the charge disposition upon said record medium solely in response thereto.

3. Means for electrostatically recording light information upon a record medium comprising means for placing an electric charge of a given polarity with respect to a fixed reference potential upon one surface of said record medium, a source of potential presenting a voltage of predetermined magnitude with respect to said fixed reference potential, said voltage being. opposite in polarity to said given polarity, converter means for changing the light information into correspondingly shaped electrical charge patterns on a given surface of said converter, said converter means comprising a plurality of elongated light guides clad along their longitudinal surfaces and one end thereof with a photoconductive material, said photoconducti-ve material on said one end of each guide forming at least a portion of said given surface, means for connecting said source of potential to the photoconductive material on the longitudinal surface of said light guides, and means for selectively irradiating the other ends of said light guides in accordance with the light information to be recorded to selectively apply said opposite polarity to said given surface to provide charge patterns shaped in accordance with said light information, said record medium being supported With said one surface in proximity to said given surface of said converter, said predetermined magnitude of the charge upon said record medium and the magnitude of said charge patterns being sufficient to create a change in the charge disposition upon said record medium solely in response thereto.

4. Means for electrostatically recording light information upon a record medium comprising means for placing an electric charge of a given polarity disposed upon one surface of said record medium, a source of potential presenting a predetermined voltage, converter means for changing the light information into correspondingly shaped electrical charge patterns on a given surface of said converter, said converter means comprising a plurality of elongated light guides spaced apart one from another defining therebetween a predetermined spacing, a layer of photoconductive material disposed within said spacing along said elongated light guides, means for connecting said given surface of said converter to a given terminal of said source of potential, said connecting means including said photoconductive material, said terminal being of a polarity opposite to said predetermined polarity, means for selectively irradiating said converter means in accordance with the light information to be recorded to selectively apply said opposite polarity to said given surface to provide charge patterns shaped in accordance With said light information, said record medium being supported with said one surface in proximity to said given surface of said converter whereby said opposite charge patterns of said converter. change the charge disposition upon said record medium in accordance with the charge pattern upon said given surface and means for bringing electrostatically attractable materials in contact with said record medium to thereby reproduce said information.

5. Means for recording light information electrostatically upon a record medium having electrostatic charges disposed on one of its surfaces, said charges being of a predetermined polarity and magnitude with respect to a fixed reference potential, 2. source of potential presenting a voltage of predetermined magnitude which is opposite in polarity to said predetermined polarity, converter means for changing light information into corresponding electrical charge patterns upon a surface thereof, said converter means comprising means including a plurality of enlongated light guides clad along their longitudinal surfaces and one end thereof with a photoconductive material for selectively connecting said source of potential to predetermined areas of said surface to provide a charge pattern of said opposing polarity thereon in en response to the selective irradiation'of said light guides and means for selectively irradiating the other ends of said light guides, said converter means being positioned so that said opposing charge pattern upon said surface is in electrical charge influencing relation to the charge disposition of said predetermined polarity on the record medium, said predetermined magnitude of the charge on said record medium and the magnitude of said charge pattern being sumcient to create an electric field of sulficient intensity to change the charge disposition of said predetermined polarity solely in response thereto to thereby create a charge pattern upon said record medium in conformity with said charge pattern upon said surface of said converter means. 1

6. Apparatus for recording light information upon a precharged record medium, the record medium having disposed thereon electrostatic charges of predetermined polarity and magnitude with respectto a fixed reference potential, a source of potential opposite in polarity to said predetermined potential and of predetermined magnitude, a light responsive converter means connected to said source of potential and positioned adjacent said record medium for converting light to a charge pattern of said opposing polarity upon a surface thereof, said surface being adjacent the record medium, the distance between said surface and the charged surface of said record medium and the potential difference between said surfaces being so related that the charge upon said record medium is influenced solely in response to said charge pattern upon said surfaces to thereby create a charge pattern upon said record medium corresponding thereto, the improvement in said converter means comprising a plurality of elongated light guides clad along their longitudinal surfaces and one of their ends with a photoconductive material, the photoconductive material on said one end of each light guide forming at least a portion of said converter means surface and means for connecting said source to said photoconductive material on the longitudinal surfaces of said guides.

7. In a printer comprising a record medium capable of accepting and retaining charges upon a given surface thereof, means for placing a uniform electrostatic charge of a given polarity With respect to a fixed reference potential upon said given surface, a source of light information, converter means located solely on said given surface side of said record medium for selectively creating a charge pattern of polarity opposed to said given polarity upon a surface of said converter in accordance with the light information supplied thereto, said converter means being located with said surface in spaced relationship with respect to said given surface of said record medium, said charge pattern and said uniform charge being of magnitudes sufficient to create an electric field of sufiieient intensity to alter said uniform charge in accordance with said charge pattern, and means for supplying light information from said source to said selected charging means, the improvement in said converter means comprising a photoconductive layer, a transparent conductive layer connected to said source of potential, a plurality of light guides, the longitudinal surfaces of which carry a photo- 7 conductive material, said light guides being interposed between and in electrical contact with said transparent conductive layer and said photoconductive layer, the free De Witt g Apr. 26, 1960 

1. MEANS FOR RECORDING LIGHT INFORMATION ELECTROSTATICALLY UPON A RECORD MEDIUM COMPRISING SAID RECORD MEDIUM HAVING ELECTRIC CHARGES DISPOSED UPON ONE OF ITS SURFACES, SAID CHARGES BEING OF A PREDETERMINED POLARITY AND MAGNITUDE WITH RESPECT TO A FIXED REFERENCE POTENTIAL, A PHOTOCONDUCTIVE LAYER DISPOSED ADJACENT BUT SPACED APART FROM SAID RECORD MEDIUM, A CONDUCTIVE TRANSPARENT LAYER, A PLURALITY OF ELONGATED LIGHT GUIDES BUNDLED TOGETHER IN SPACED APART RELATION ONE TO THE OTHER DEFINING THEREBETWEEN ALONG THE ELONGATION OF SAID GUIDES A PREDETERMINED SPACING, PHOTOCONDUCTIVE MATERIAL DISPOSED WITHIN SAID SPACING ALONG SAID ELONGATED LIGHT GUIDE FOR RESPONDING TO LIGHT FROM THE ADJACENT GUIDE TO RENDER THE ADJACENT PHOTOCONDUCTIVE MATERIAL CONDUCTIVE, SAID LIGHT GUIDE AND SAID PHOTOCONDUCTIVE MATERIAL ASSEMBLY BEING INTERPOSED BETWEEN AND CONTIGUOUS WITH SAID CONDUCTIVE LAYER AND SAID PHOTOCONDUCTIVE LAYER, A SOURCE OF POTENTIAL PRESENTING AT LEAST A PREDETERMINED VOLTAGE OPPOSITE IN POLARITY TO SAID PREDETERMINED POLARITY, SAID PREDETERMINED VOLTAGE BEING CONNECTED WITH THAT CONDUCTIVE LAYER AND ESTABLISHING THEREON AN ELECTRIC POTENTIAL CHARGE DISPOSITION OF A POLARITY OPPOSING SAID PREDETERMINED POLARITY, AND MEANS FOR SELECTIVELY IRRADIATING SAID LIGHT GUIDES AND SAID PHOTOCONDUCTIVE MATERIAL TO ACTIVATE SAID PHOTOCONDUCTIVE LAYER SO AS TO PRESENT THAT POLARITY IN ELECTRIC CHARGE INFLUENCING RELATION TO THE CHARGE DISPOSITION OF SAID PREDETERMINED POLARITY, SAID PREDETERMINED MAGNITUDE OF THE CHARGE ON SAID RECORD MEDIUM AND THE MAGNITUDE OF SAID CHARGE PATTERNS BEING SUFFICIENT TO CREATE A CHANGE IN THE CHARGE DISPOSITION OF SAID PREDETERMINED POLARITY SOLELY IN RESPONSE THERETO TO THEREBY CREATE A CHARGE PATTERN UPON SAID RECORD MEDIUM IN CONFORMITY WITH THE SAID CHARGE PATTERN ON SAID PHOTOCONDUCTIVE LAYER. 